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Fast Forward by Rob Pegoraro

The Digital Transition

By Rob Pegoraro
Sunday, August 29, 2004; Page F01

If my car died tomorrow, I'd have a lot less angst picking its successor than I would if my TV conked out. The "digital transition," as it's called, has given the television market some of the same frustrating inscrutability as the computing market, with an extra dose of technological, regulatory and economic uncertainty.

And yet: People are buying these things. Not just the techno-victims who will snap up any unproven gadget with a four-figure price tag, but regular folks who simply want a better set when their old one implodes.

Video: Rob Pegoraro discusses the confusion surrounding HDTV
_____Decoding Digital TV_____
Your Questions Answered: Recording, Shopping, More
To Be Picture-Perfect, a Choice of 3 (The Washington Post, Aug 29, 2004)
_____Live Discussion_____
Transcript Rob Pegoraro was online to answer your HDTV questions.
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Finding that better set without buying more or less than you actually want is the real trick of the digital-TV market. Here are six riddles to keep in mind:

Digital and high-definition TV aren't the same thing, except when they are. HD is a subset of digital TV, a generic term that covers 18 possible combinations of picture resolution, screen proportions, scan mode and frame rate. Only six of them count as HDTV -- only two of which broadcasters actually use.

(Why 18 digital-TV formats if so few are used? Much of the consumer-electronics industry remains stuck at a kindergarten-playground level of conflict resolution; when the Federal Communications Commission had to pick a standard in the mid-1990s, embracing all 18 formats available was the best it could do.)

One of the two HD formats is called 720p to indicate its 720 progressively scanned lines of resolution; "progressive" means that the entire image on the screen is refreshed 60 times a second, the way a computer monitor works. The other is 1080i, for 1,080 interlaced scan lines; in this case, half of these lines are refreshed every 60th of a second, the way old-fashioned analog TV works. Both 720p and 1080i are wide-screen formats, with a 16:9 aspect ratio close to a movie-theater screen's proportions.

Vendors, however, often try to fudge whether a set is HD-capable in ads. Pay attention to an HD set's resolution -- except when it doesn't matter.

Many digital sets -- including some large, pricey plasma screens -- only support a third, lower-resolution format called 480p (short for 480 progressive scan lines). This format, still a big step up from analog TV (which uses 480 interlaced scan lines), is often marketed as "Enhanced Definition." But on those 42-inch plasmas, the difference between ED and HD won't be hard to spot. When in doubt, look up a set's resolution in pixels; if its vertical resolution (the second number listed in a figure like "640 x 480") is below 720, it's not HD.

Conversely, on smaller sets -- say, under 25 inches across -- it is difficult to see the difference between 480p and 72op or 1080i from normal viewing distances. On those televisions, you can get away with enhanced definition, saving yourself a few bucks.

Like analog TV, digital TV broadcasts can be received in a variety of ways -- over the air, or, for a much larger selection of channels, over cable or via satellite. But digital cable or digital satellite isn't the same thing as digital TV. The services that cable and satellite providers have sold for years are analog at heart; they're only "digital" in the way they transmit that conventional signal. Real, HD-capable digital TV via cable or satellite costs more than "digital" cable or satellite and brings a smaller selection; many cable channels haven't brought out HD versions, although this is quickly improving.

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